Countess Iseara gives a unit Necormancy until the end of the turn. Does a unit keep necromancy even if you sarifice it? If this is correct, than it would be possible to gain infinite cards (walking sacrifice) or infinite damage (Fledgling Chaos Spawn) if you have a warpstone excaption and a Great Unclean One in addition to infinite power on the Great Uncleane One.
There is a similar combination in this thread by Zeruul:
http://www.fantasyflightgames.com/edge_foros_discusion.asp?efid=155&efcid=4&efidt=362898&efpag=0#363121 (link did not work)
But this one is a lot easier to achieve, because it consists of only 4 cards and two are without cost.